An M2M communication environment according to the present invention will be described below in brief.
As its appellation implies, M2M communication refers to communication between electronic devices. In a broad sense of the term, M2M communication means wired or wireless communication between electronic devices or communication between a human-controlled device and a machine. Recently, it is typical to mean wireless communication between electronic devices without human intervention by M2M communication.
In the early 1990s when the concept of M2M communication was introduced, M2M communication was regarded merely as remote control or telematics and its market was very limited. However, the past few years have witnessed the rapid development of M2M communication and thus its market has been boosted so much as to attract worldwide interest. Particularly, M2M communication has significantly affected fleet management in Point Of Sales (POS) and security-related application markets, remote monitoring of machines and facilities, operation time measurement of construction machines, and smart metering of automatically measuring heat or electricity consumption.
M2M communication will find its applications for various usages in conjunction with legacy mobile communication, ultra-high speed wireless Internet, or low-power communication solutions such as Wireless Fidelity (Wi-Fi) and Zigbee. Therefore, M2M communication will expand its market to a Business to Consumer (B2C) market beyond a Business to Business (B2B) market.
In the era of M2M communication, every machine equipped with a Subscriber Identity Module (SIM) card is capable of data transmission and reception, thus allowing remote management and control. For example, the application range of the M2M communication technology is very broad, inclusive of many devices and equipment such as vehicle, truck, train, container, automatic vending machine, gas tank, etc.
Conventionally, terminals are usually managed individually and thus one-to-one communication is conducted between a base station and a terminal If a number of M2M devices communicate with a base station in a one-to-one communication scheme, it is expected that signaling between each of the M2M devices and the BS will cause network overhead. As described before, if M2M communication becomes rapidly widespread, overhead caused by communication between M2M devices or between M2M devices and a base station may be a problem.
Particularly when many M2M devices are located within the area of one base station, all of the M2M devices may perform a ranging procedure for initial network entry or network reentry from idle mode. In this case, there may be a shortage of ranging codes for the M2M devices. If the M2M devices perform the ranging procedure simultaneously, the network may suffer from overhead and the ranging procedure may not be performed normally due to collision between M2M devices during ranging.
A primary requirement for M2M devices is low power consumption. Therefore, if all M2M devices perform ranging to a base station, the power consumption of the M2M devices is high.